A novel catalyst cobalt <i style="">m</i>-nitrobenzenesulfonate-catalyzed highly efficient synthesis of substituted-quinazolin-4(1<i style="">H</i>)-ones

Abstract

A highly efficient synthesis of mono- and disubstituted 2,3-dihydro-quinazolin-4(1<i style="">H</i>)-ones has been performed by the condensation of isatoic anhydride, aldehydes, and ammonium salts or amines in EtOH/H₂O under reflux. A novel water-tolerant Lewis acid, cobalt <i style="">m</i>-nitrobenzenesulfonate, has been prepared and applied as a favorable catalyst in this one-pot three-component cyclocondensation reaction. The optimal amounts of catalyst and solvent are investigated. Experimental results show that only 3 mol% catalyst is enough to induce the conversion and EtOH/H₂O [1/3 (v/v)] system is observed as the best choice. All the reactions are performed within a short reaction time and the catalyst is easily recovered and recycled. The structures of new compounds are characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. A mechanism to rationalize the reaction is proposed.